ABSTRACT
The economic threshold for the second generation of grape moths based on attack and damage levels at harvest is not useful, since treatment must be given in July.
The relationship between catches on pheromone traps and attacks do not always allow a decision on whether to treat or not.
The “anticipated” economic threshold based on egg-laying on grapes (1 – 10% bunches with visible eggs) presents some sampling difficulties.
The first larval holes on the grapes are easier to observe than eggs. A sampling method based on the first larval holes (10 – 15 days after the emergence peak of male moths) is reported.
The new economic threshold is based on the analysis of the evolution of attacks and damages. In particular, it has been observed that:
The groups of rotten grapes, visible on mature bunches, are the consequence of perforations on unripe grapes, made by second generation larvae.
A good relationship has been found between early larval attacks (10 – 15 days after the emergence peak of male moths) and final attacks.
Penetrating insecticides allow a successful treatment even 10 – 15 days after the emergence peak of male moths.
